Document Detail


Physiology of intermittent feeding: integrating responses of vertebrates to nutritional deficit and excess.
MedLine Citation:
PMID:  16555185     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Food intakes of wild animals may not match their requirements for nutrients and energy but may vary between periods of nutritional excess (hyperphagia) and nutritional deficit (hypophagia) at timescales that vary from days to months. We present a simple model of feeding patterns and requirements of vertebrates. Frequent fasts and high intakes are typical of endothermic predators and migratory birds, whereas slow cycles and long deficits typify feeding patterns of ectothermic predators and ungulates in seasonal environments. We propose that hyperphagia is constrained by the ability to increase processes of digestion, absorption, intermediary metabolism, net deposition in tissue, and excretion to match loads of digesta and metabolites. Hyperphagia on high-quality diets is limited by the clearance of metabolites, whereas digestive tract capacity and flow limit consumption of low-quality diets. Of all digestive strategies, small omnivores with simple digestive systems may be the most tolerant of frequent hyperphagia. Tolerance of hypophagia favors large endogenous stores or low mass-specific rates of metabolism and reproductive output. Large animals may be most able to sustain reproduction during prolonged deficits in seasonal environments. Responses to excessive and deficient intakes of food are constrained by the length of the feeding cycle. Animals adapted to short feeding cycles may be best suited to unpredictable food supplies but at the energetic cost of maintaining spare capacity for digestion and absorption. Predictions of the response to food disruption are best evaluated in the context of body size, nutritional physiology, and life history of the species and the time for internal response.
Authors:
Perry S Barboza; Ian D Hume
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Publication Detail:
Type:  Journal Article     Date:  2006-02-07
Journal Detail:
Title:  Physiological and biochemical zoology : PBZ     Volume:  79     ISSN:  1522-2152     ISO Abbreviation:  Physiol. Biochem. Zool.     Publication Date:    2006 Mar-Apr
Date Detail:
Created Date:  2006-03-23     Completed Date:  2006-06-09     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100883369     Medline TA:  Physiol Biochem Zool     Country:  United States    
Other Details:
Languages:  eng     Pagination:  250-64     Citation Subset:  IM    
Affiliation:
Department of Biology and Wildlife, Institute of Arctic Biology, P.O. Box 757000, University of Alaska, Fairbanks, AK 99775-7000, USA. ffpsb@uaf.edu
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MeSH Terms
Descriptor/Qualifier:
Animal Nutritional Physiological Phenomena*
Animals
Ecosystem
Energy Metabolism / physiology
Fasting / physiology
Feeding Behavior / physiology*
Food
Models, Biological
Time Factors
Vertebrates / physiology*

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